Aspartame use in Parkinson's disease

Area of Science:

• Neuroscience
• Pharmacology
• Nutritional Science

Background:

• Aspartame is hydrolyzed to phenylalanine (PA), a large neutral amino acid (LNAA).
• LNAAs compete with levodopa for brain uptake, potentially affecting Parkinson's disease (PD) treatment.
• Protein-sensitive motor fluctuations are common in levodopa-treated PD patients.

Purpose of the Study:

• To investigate the effect of aspartame consumption on levodopa efficacy in PD patients.
• To determine if aspartame intake exacerbates motor symptoms in individuals with protein-sensitive fluctuations.

Main Methods:

• Double-blind, single-crossover study involving 18 PD patients.
• Administration of aspartame (600 or 1,200 mg) and placebo on alternate days.
• Hourly motor examinations and blood sampling for plasma LNAA, PA, and levodopa levels.

Main Results:

• 600 mg of aspartame had no impact on plasma PA or motor status.
• 1,200 mg of aspartame increased plasma PA but did not lead to motor deterioration.
• Aspartame consumption, even in excess of typical intake, did not adversely affect PD patients.

Conclusions:

• Aspartame consumption does not negatively impact motor control in PD patients on levodopa therapy.
• The phenylalanine metabolite of aspartame does not interfere with levodopa's therapeutic effects at tested doses.
• PD patients can safely consume aspartame-sweetened products without compromising their motor function.